Gigantic study: no Xq28 gene does not define sexual orientation
In 1993, a study of 40 families had thought to identify a unique place, the Xq28 gene, defining sexual orientation.
This study made it possible to confuse certain "homophobes" who wanted to bring homosexuals back on the "right path" by telling them that these efforts would be in vain since these homosexuals were born that way; their homosexuality was in no way a matter of choice or bad influences.
A new and gigantic analysis refutes this simplistic genetic model.
This is the conclusion of an analysis conducted on half a million DNA profiles by a group of researchers in Europe and the United States, whose publication Thursday by the prestigious journal Science aims to bury the idea born in the 1990s that there is a "gay gene" as predictable as what exists for the color of the eyes. "It's de facto impossible to predict a person's sexual orientation based on their genome," says Ben Neale, a member of Harvard Broad Institute and MIT, one of the many institutions from which the authors come.
Sexual orientation may have a genetic component, the researchers say, confirming earlier, smaller studies, especially on twins.
This is the case for many other traits, see Why education plays a less important role than we think.
But this component depends on a myriad of genes and the environment where the person is growing up. "There is no single homosexual gene, but many small genetic effects distributed throughout the genome," says Ben Neale. Added to this is an essential factor:
the environment in which a person grows up and lives.
To better explain, researchers compare to size: the genetic effect is indisputable, since your size is linked to that of your parents. But genetics does not explain everything: your nutrition during childhood will have a significant impact. This is what scientists call the environment. Ditto for cardiac risk: genes create predispositions, but your lifestyle, like your diet, has a bigger role.
The new statistical analysis revealed five precise positions on our chromosomes, called locus, which appear to be clearly related to sexual orientation, although each has a "very small" influence. Biologically, it turns out that a marker is also associated with hair loss, suggesting a link with the regulation of sex hormones. Presumably, there are hundreds or thousands of other markers, which future analyzes on larger DNA banks might one day discover.
"It's a complex behavior where genetics plays a role, but probably in a minority way. The effect of the environment exists,
but we can not measure it exactly, "adds Fah Sathirapongsasuti, a scientist at 23andme.com,
a DNA testing site that contributed to the study with genetic profiles of clients ( volunteers).
The bulk of the analysis was made of men and women from the UK-based British Biobank, mostly of European origin, who answered the question:
Have you ever had sex with a person of the same sex?
This study made it possible to confuse certain "homophobes" who wanted to bring homosexuals back on the "right path" by telling them that these efforts would be in vain since these homosexuals were born that way; their homosexuality was in no way a matter of choice or bad influences.
A new and gigantic analysis refutes this simplistic genetic model.
This is the conclusion of an analysis conducted on half a million DNA profiles by a group of researchers in Europe and the United States, whose publication Thursday by the prestigious journal Science aims to bury the idea born in the 1990s that there is a "gay gene" as predictable as what exists for the color of the eyes. "It's de facto impossible to predict a person's sexual orientation based on their genome," says Ben Neale, a member of Harvard Broad Institute and MIT, one of the many institutions from which the authors come.
Sexual orientation may have a genetic component, the researchers say, confirming earlier, smaller studies, especially on twins.
This is the case for many other traits, see Why education plays a less important role than we think.
But this component depends on a myriad of genes and the environment where the person is growing up. "There is no single homosexual gene, but many small genetic effects distributed throughout the genome," says Ben Neale. Added to this is an essential factor:
the environment in which a person grows up and lives.
To better explain, researchers compare to size: the genetic effect is indisputable, since your size is linked to that of your parents. But genetics does not explain everything: your nutrition during childhood will have a significant impact. This is what scientists call the environment. Ditto for cardiac risk: genes create predispositions, but your lifestyle, like your diet, has a bigger role.
The new statistical analysis revealed five precise positions on our chromosomes, called locus, which appear to be clearly related to sexual orientation, although each has a "very small" influence. Biologically, it turns out that a marker is also associated with hair loss, suggesting a link with the regulation of sex hormones. Presumably, there are hundreds or thousands of other markers, which future analyzes on larger DNA banks might one day discover.
"It's a complex behavior where genetics plays a role, but probably in a minority way. The effect of the environment exists,
but we can not measure it exactly, "adds Fah Sathirapongsasuti, a scientist at 23andme.com,
a DNA testing site that contributed to the study with genetic profiles of clients ( volunteers).
The bulk of the analysis was made of men and women from the UK-based British Biobank, mostly of European origin, who answered the question:
Have you ever had sex with a person of the same sex?
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